Wiring help – Bathroom light, fan, & heater. No red wire AND is white hot

bathroomwiring

So I read and read and no one quite seemed to have the same scenario as me. I'd give my self a Basic Plus to intermediate rating for electrical, pretty decent understanding but some of the lingo eludes me.

I have 2 wires (plus ground) coming out in 2 sets. One controls light & fan the other appears to control only the heater. I got an almost direct replacement. However, the diagram sure doesn't match what i have – no red wire and a sneaking suspicion the white to the heater was hot, not neutral. See pic with white tied to red. Red (from unit) is hot.

I took the best pics I could at the time (not great). Bit of a tangled mess before removing. Prior to replacing, the white wire definitely goes to the red (hot for the heater right?) which goes against the diagram and everything else I read. I got worried about switching cuz the second answer from isherwood in this post made made me wonder if I fit this description. <- This guy's post looks almost identical to my model except his wiring is slightly different.

So the 2 things messing me up is: is that white hot? What about the diagram and my lack of a red wire?

The fan/light looks fairly straight forward with the whites all tied together and black to black, except that darned blue to red…

I should also mention that 3 different switches independently control each function, so no tie ins or whatever.

Big thanks ahead of time!

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Ok, so I stuck my tongue out and tried different combos of wires….No, got the multi meter out and confirmed the right side wires are indeed backwards (white = hot, nothing on the black). Th left side branch is how it should be. Took some photos of the switch box as well. Ignore the right most switch, not related. They're labeled in pics. The white with post it note (if you can't read it) is the hot white.

  • For the heater: the hot white to red (heater), black to the white (seriously?? who did this wiring?), ground is obvious. Should I swap the wiring on the switch and reverse it? Or just tape it/label it accordingly.

  • For the correctly routed/colored one – since there is no red wire: black AND blue go to the black from wall (the hots), a bundle of whites (from ceiling with other 2 tied together), again ground obvious.

Thanks for all the input.

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Best Answer

Your installation (as it was) needed 3 hots and 1 neutral. I suspect the original installer didn't want to bother sourcing /4 cable or using smurf tube, so simply doubled up two /2 cables and called it a day. As such, one of the whites is being used as a hot. "Misused", probably. NEC is not as clear on this point as I would like.

If you don't want to correct that, make sure to have the black with the real neutral serve the heater, to minimize the numerous reasons why ganging 2 cables like that is problematic.

Otherwise the way to do it with existing cabling is to de-task white back to a neutral, and make one switch control light+fan together. Like their drawing, but tie the socket black and blue together.

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